(Reuters) – Bristol-Myers Squibb said on Wednesday its experimental drug helped reduce the severity of the most common form of psoriasis in a mid-stage trial.

The study tested the drug, BMS-986165, in 267 patients with plaque psoriasis, a chronic condition that causes dry, red skin lesions covered with silvery scales.

After 12 weeks, between 67 percent and 75 percent of patients given a 3-milligram dose twice daily, or a higher dose, showed a 75 percent reduction on a scale called PASI that is considered the benchmark of main goals for most psoriasis clinical trials.

The PASI showed a 75 percent reduction in only 7 percent of patients in the placebo group. It measures the effectiveness of a drug by recording how many patients achieve a reduction in the area affected and severity of their psoriasis.

The drug is a tyrosine kinase 2 inhibitor, a class of medicines that work to regulate overactive immune responses that drive autoimmune diseases.

Three cases of serious side effects were reported, but none of those were in patients given the 6-mg and the 12-mg doses, the highest being tested, the company said.

Bristol-Myers said it plans to study the drug’s use in a “wide spectrum of immune-mediated diseases”, saying currently only few oral treatment options are available.

The company is currently enrolling patients for a late-stage trial and also testing BMS-986165 for use in patients with lupus or Crohn’s disease.

An approval by the U.S. Food and Drug Administration for the plaque psoriasis treatment will offer Bristol-Myers, which relies heavily on its blockbuster cancer drug Opdivo, a chance to diversify its portfolio.

The FDA earlier this year declined to approve Bausch Health Cos Inc’s plaque psoriasis lotion Duobrii and analysts now expect that drug to hit market only after 2019.

(This version of the story corrects scale name to “PASI”, from “PASI-75”, in paragraph 3 and 4)

(Reporting by Tamara Mathias in Bengaluru; Editing by Sriraj Kalluvila)